modified readme

README.md

@@ -2,37 +2,58 @@
 
 A simple go app that reads SNMP values and publishes it to the specified MQTT endpoint at the specified interval.
 
-Please download the precompiled binary from the releases page: https://github.com/dchote/snmp-mqtt/releases
+In constrast to the original version, all configuration must be provided via an environment variable containing
+a JSON string. 
+
+The MQTT configuration is part of this JSON string.
+
+The topic has been moved to the MQTT configuration and there is now only one topic for all endpoints and variables.
+
+The published message on MQTT looks like this:
 
 ```
-Usage: snmp-mqtt [options]
+{"device":"172.16.3.1","label":"router","variables":{"lan-in":{"label":"lan-in","variable":".1.3.6.1.2.1.31.1.1.1.6.2","value":"979673705579"},"lan-out":{"label":"lan-out","variable":".1.3.6.1.2.1.31.1.1.1.10.2","value":"1813410276168"},"wan-in":{"label":"wan-in","variable":".1.3.6.1.2.1.31.1.1.1.6.4","value":"83591215399"},"wan-out":{"label":"wan-out","variable":".1.3.6.1.2.1.31.1.1.1.10.4","value":"83741895468"}}}
-
-Options:
-  --endpoints_map=<endpoints_map>     SNMP Endpoints Map File [default: ./endpoints.json]
-  --server=<server>                   MQTT server host/IP [default: 127.0.0.1]
-  --port=<port>                       MQTT server port [default: 1883]
-  --topic=<topic>                     MQTT topic prefix [default: snmp]
-  --clientid=<clientid>               MQTT client identifier [default: snmp]
-  --interval=<interval>               Poll interval (seconds) [default: 5]
-  -h, --help                          Show this screen.
-  -v, --version                       Show version.
 ```
 
-An example endpoints.json file:
+```
+export SNMP_MQTT_CONF=$(cat config.json)
+./smq
+```
+
+An example config.json file:
 ```
 {
+  "mqtt": {
+    "broker": "mqtt://172.23.1.102:1883",
+    "tlsEnable": "false",
+    "topic": "snmp"
+  },
+  "interval": 10,
   "snmpEndpoints": [
     {
-      "endpoint": "172.18.0.1",
+      "endpoint": "172.16.3.1",
+      "label": "router",
       "community": "public",
       "oidTopics": [
         {
           "oid": ".1.3.6.1.2.1.31.1.1.1.6.4",
-          "topic": "router/bytesIn"
+          "label": "wan-in",
+          "diff": "true"
         },
         {
           "oid": ".1.3.6.1.2.1.31.1.1.1.10.4",
-          "topic": "router/bytesOut"
+          "label": "wan-out",
+          "diff": "true"
+        },
+        {
+          "oid": ".1.3.6.1.2.1.31.1.1.1.6.2",
+          "label": "lan-in",
+          "diff": "true"
+        },
+        {
+          "oid": ".1.3.6.1.2.1.31.1.1.1.10.2",
+          "label": "lan-out",
+          "diff": "true"
         }
       ]
     }